The present invention relates to utility lifting assemblies and, in particular, to a low-profile, castered, multi-purpose assembly adaptable to a variety of general and automotive repair applications.
A problem long plaguing automotive and heavy equipment repair and maintenance personnel is how to efficiently handle major equipment subassemblies, such as transmissions, differential gears, axles and the like, where the vehicle weight is sufficiently great to the point where a vehicle hoist is either unable or unavailable to lift the vehicle to comfortable working height. Although repair pits have been used in some of such circumstances, the problem still remains of how to manipulate and manhandle the vehicle subassembly, especially when it weighs hundreds of pounds. When using a pit, one might detach the subassembly and capture it on a lower upright support, prior to manually pushing the vehicle away from the pit to permit removal of the subassembly from beneath the vehicle. Needless to say, such efforts are rather tedious and difficult, especially for vehicles capable of supporting loads in excess of one ton.
Where a pit is unavailable and one is unable to lift the entire vehicle, jacking assemblies can be manipulated beneath the vehicle to raise a portion of it. One may then work beneath the chassis on one's back or in a seated posture on an associated castered dolly or the floor. One's posture and efficiency however suffer when working in this fashion, since this posture must be maintained until the subassembly is removed.
The physical removal of the subassembly again occurs in a sequential process which requires detaching and supporting the subassembly, raising the vehicle away from the subassembly or lowering the subassembly and withdrawing the subassembly. The only advantage in the above removal sequence is that the vehicle need not normally be moved. Otherwise, it is as tedious as using a pit.
Although Applicant is aware of various transmission supports which are usable beneath a raised vehicle and engine lifts or so called "cherry picker" arrangements which find application when removing an engine from above the vehicle without the aid of a vehicle lift, Applicant is not aware of any such assembly which may be selectively assembled to the task at hand and be operated from beneath the vehicle. Nor is Applicant aware of any assembly which permits the alternative grasping and raising the subassembly in the space between the vehicle chassis and subassembly or the space between the floor and subassembly. Although various hydraulic floor jacks might be used in latter circumstance, since they provide an underlying lift force as opposed to an overlying force, this is not always possible, due to minimal ground space clearance between the floor and subassembly.
Applicant is also aware of a variety of early patents which disclose a number of a low-profile lifting devices which variously depend on a mechanical jack mechanism or a hydraulic mechanism. Of the former type, applicant is aware of U.S. Pat. Nos. 4,690,378; 3,749,361; 3,154,206; 3,011,763; and 2,575,160. Specifically, the 3,154,206 and 3,749,361 Pat. Nos. disclose castered jacking assemblies including screw operated lift towers and ratchet lift towers, the later of which include singular replaceable lift heads of differing constructions. The 2,575,160 and 4,690,378 patents disclose a pair of low-profile, castered jacks which operate relative to scissors acting lift mechanisms which may also include replaceable singular lift attachments for grasping the surface to be raised. The 3,011,763 Pat. discloses an elongated hydraulic lift assembly with remotely mounted operating mechanisms.
Applicant is additionally aware of two other hydraulic lift assemblies which are disclosed in U.S. Patent Nos. 4,479,632 and 3,040,908. Of these, the former patent discloses a jacking assembly for accessing a subassembly from above the vehicle. In particular, it discloses an engine hoist wherein a primary, pivotally mounted lift arm is hydraulically raised. Coupled to the forward end of the lift arm are secondary hydraulic lift assemblies for tilting and otherwise adjusting a pivotal fore end of the lift arm. The later patent discloses a low-profile jacking assembly more of the type of the present invention for accessing a subassembly from beneath the raised chassis. It too provides for a pivotally mounted fore end including associated screw means for changing the tilt angle of the work piece grasping end of the assembly.
Although the later assembly is relevant to some circumstances wherein the present invention finds particular advantage, the fore end tilt control assemblies do not accommodate the wide range of circumstances that oftentimes arise when working on a variety of makes and models of vehicles, be it an automobile, truck or motorcycle.
The preference therefore is to have available a low-profile, castered lift assembly which accommodates a variety of detachable, adjustable working heads for appropriately lifting or supporting a subassembly relative to the available clearance space between the vehicle and/or ground. A multiplicity of interlocking heads provides greater freedom and ability to meet the needs of a specific circumstance, rather than the limited range adjustment provided by singular moveable heads having only limited degrees of tilting freedom.